1. Field of the Invention
The invention relates to a wheelchair, more particularly to a wheelchair that is capable of absorbing road shock.
2. Description of the Related Art
Power wheelchairs have become a mode of transport for the handicapped and the elderly. A power wheelchair usually has a pair of drive wheels mounted on opposite lateral sides of a chair frame, and two front wheels and two rear wheels mounted in front and behind the drive wheels, respectively. A drive device is mounted on the chair frame for driving the drive wheels. The power wheelchair is also provided with a set of shock absorbers for absorbing road shock so as to enhance user comfort.
Referring to FIGS. 1 and 2, a conventional power wheelchair 1 is shown to include a chair frame 11 mounted with a drive device (not shown). The chair frame 11 includes an intermediate frame part 111 and a pair of lateral frame parts 112 fixed to opposite ends of the intermediate frame part 111, respectively.
Each of a pair of suspension arms 131 is connected pivotally to a bottom side of the intermediate frame part 111 through a respective pivot axle 130, and is disposed below a respective one of the lateral frame parts 112. Each of a pair of clutches 132 is mounted fixedly on a respective one of the suspension arms 131. Each of a pair of drive wheels 133 is coupled to a respective one of the clutches 132. Each of a pair of shock absorbers 134 is mounted between a respective one of the lateral frame parts 112 and a respective one of the suspension arms 131, and is capable of absorbing road shock forces.
When the drive wheels 133 of the power wheelchair 1 move on an uneven road, because the drive wheels 133 are connected to the suspension arms 131 through the clutches 132, the suspension arms 131 are able to pivot accordingly about the pivot axles 130, and the shock absorbers 134 operate to absorb road shock forces so as to minimize user discomfort.
However, when the drive wheels 133 are subjected to lateral forces, because no mechanism is provided for limiting lateral movement of the suspension arms 131, the pivot axles 130 are easily twisted and deformed such that the shock-absorbing effect is affected undesirably.